1. Field of the Invention
The present invention is directed to a hearing aid, and in particular to a hearing aid adaptable for telephone listening to produce a tone comfortable for the user.
2. Description of the Prior Art
Hearing aids are known which include a separate coil, in addition to the microphone normally used, to capture the magnetic field from a telephone receiver, and to convert it into corresponding signals for the hearing-impaired person. The accommodation of such an additional coil, however, is frequently impossible for space reasons in smaller hearing aids, such as in-the-ear hearing aids. Although it is theoretically possible to conduct telephone listening using the microphone present in the hearing aid for normal use, acoustic reproduction quality is poor when this microphone is used to receive signals from the telephone receiver because of the closeness of the hearing aid microphone to the transmitting speaker in the telephone hand piece. Hearing-impaired persons complain that an unnatural, piercing, shrill tone results under such circumstances.